Within hours of the attack in Lahore, the Islamist terrorist group Lashkar-e-Taiba, which mounted the spectacular assault on Mumbai, killing 172 people, was being named as the prime suspect. Officials pointed out marked similarities in the two operations: a well-drilled group staging a commando-style raid; the choice of high-profile targets with the guarantee of widespread international publicity; similar types of weapons used by gunmen dressed similarly with rucksacks for extra ammunition and the nearness of Lashkar's base at the town of Muridke to Lahore city.

Salman Taseer, the governor of central Punjab province, said: "It's the same pattern, the same terrorists who attacked Mumbai, the kind of arms they had, the way they attacked."

Another theory was that Sri Lanka's bitter civil war, with its recent upsurge of fighting, has spread abroad, with the Tamil Tigers either directly involved in the assault or had planned it, using Pakistani proxies. But Tamil separatists have never operated on Pakistani soil, are not known to have such ties with Islamists and, it is pointed out, the Sri Lankan cricket team has Tamil as well as Sinhalese members.

The general consensus last night was that a home-grown Pakistani group was responsible for the ambush. Lashkar are not the only militants under suspicion in a country which has become synonymous with terrorism. Tehrik-e-Taliban, allied to al-Qa'ida, a militant umbrella group led by Baitullah Mehsud, was blamed by the Pakistani government for the assassination of Benazir Bhutto, and had also committed a wave of suicide bombings. But the organisation, based in south Waziristan, is not thought to be particularly strong in Lahore, and the modus operandi so far has been rural insurgency and urban bombings rather than such Mumbai-style assaults.

Some observers said Jaish-i-Mohammad, led by Maulana Masood Azhar, which attacked the Indian parliament in Delhi, as well as bombing churches inside Pakistan, may have been involved. This group is closely affiliated with Lashkar, members mounting missions on behalf of each other.

If Lashkar did make the hit on the Sri Lankan cricket team, questions would be asked about the hidden hand behind the gunmen. The group has links with the Pakistani intelligence service, ISI, and military, both repeatedly accused by the Indian and Afghan governments of orchestrating attacks in their respective countries.

There has been increasing tension between the civilian government which came into power after the last election and the security establishment, and vicious infighting between the political parties. Any evidence of Lashkar staging the attack with the encouragement of its military sponsors would point towards the country slipping further into the abyss.

Robert Emerson, a security analyst who has worked in south Asia, said: "There are various elements within the Pakistani military and intelligence set-up who appear to have special relationships with militant groups. There are also links between political and criminal organisations. It is a complex and shadowy world with conflicting agendas."

Lashkar also has connections to the murky world of Pakistani cricket. Dawood Ibrahim, a Muslim gangster boss in Mumbai, is believed to have been responsible for organising a series of bombings at the Indian city in 1993, killing 250 people, after which he fled the country for Pakistan. Ibrahim, named by the US State Department as a "global terrorist with links to al-Qa'ida and Lashkar-e-Taiba", and a major trafficker of Afghan opium, has also been accused of playing a part in the last Mumbai attack.

Victor Ivanov, the head of the Russian counter-narcotics service, said: "Evidence suggests that the regional drug baron Dawood Ibrahim had provided his logistics network to prepare and carry out the Mumbai terror attacks."

Ibrahim is also said to be involved in match-fixing scandals which have bedevilled cricket in the sub-continent. His daughter, Marukh, is married to Junaid, son of Javed Miandad, a senior official with the Pakistan Cricket Board.

There are absolutely no suggestions that Mr Miandad has any connection with terrorism, drug-dealing or match-fixing. But the link between cricket and a major terrorist suspect such as Ibrahim will add to the climate of fear driving Pakistani cricket. If that happens, then Pakistan's international matches are likely to be held in Gulf states such as Dubai where there is a large expatriate population from the sub-continent, and where Ibrahim has substantial business interests, including sports betting.

Legacy of murder: Extremist attacks in Pakistan

*2002: US journalist Daniel Pearl kidnapped in Karachi and beheaded

*2003: 47 people killed in suicide bombing at Shia mosque in Quetta

*2004: Car bomb kills 40 people and injures 100 at rally in Multan

*2006: Fifty people killed by bomb at a Muslim religious meeting in Karachi

*2007: Former prime minister Benazir Bhutto killed, with 20 others, in a shooting and suicide attack